1. Field of the Invention
Embodiments of the present invention relate generally to wireless digital communication and more specifically to power grid topology discovery via time correlation of passive measurement events.
2. Description of the Related Art
In a conventional electric power grid, high-voltage power is produced at a power station, such as a hydroelectric dam, and then conducted along power transmission lines to a power sub-station. At the power sub-station, the high-voltage power is stepped down to a medium-voltage power, which, in turn, is distributed to transformers that are dispersed geographically. Power consumers, including residences and businesses, draw power directly from such transformers.
A given transformer has a primary side that includes upstream power transmission lines, as well as a secondary side that includes power transmission lines coupled directly to power consumers. The set of power consumers coupled to a given transformer are said to reside on the secondary side of the transformer. Electric power companies typically maintain documentation specifying which power consumers reside on the secondary side of each transformer. This documentation defines the power grid topology.
Maintaining an accurate power grid topology is important to electric power companies because that topology may be used to predict loads on different parts of the power grid and to avoid safety issues related to transformer overloading, among other things. Further, the power grid topology can be used to identify unauthorized modifications to the power grid, which could also pose safety issues.
One approach to determining power grid topology involves placing a transceiver on each transformer, where a given transceiver is configured to communicate with power consumer metrology on the secondary side of the corresponding transformer using power line communication (PLC) techniques. Using PLC techniques, the transceiver associated with a given transformer attempts to identify the set of power consumers residing on the secondary side of that transformer by communicating with the associated metrology.
This approach is flawed, however, because PLC techniques are only effective over a certain distance. If a given power consumer resides sufficiently far away from the transceiver, then the metrology associated with that power consumer will not be capable of discerning the PLC signal against background noise and cannot communicate with the transceiver. As such, the transceiver located on the transformer is incapable of determining that the power consumer is coupled to that transformer, and, thus, the overall power grid topology will be inaccurate.
The drawbacks of PLC-oriented techniques for establishing power grid topology are especially pronounced in countries within the European Union, since those countries often allow a large number of power consumers to be coupled to a single transformer. Consequently, many of these power consumers reside outside of the effective range of PLC techniques, and so the topology of such power grids is at risk of being inaccurate.
As the foregoing illustrates, what is needed in the art is an improved technique for determining power grid topology.